An electronic cigarette (“e-Cig”) is a device that emulates tobacco cigarette smoking, by producing smoke replacement that may be similar in its physical sensation, general appearance, and sometimes flavor (i.e., with tobacco fragrance, menthol taste, added nicotine etc.). The device may use heat, ultrasonic energy, or other means to atomize/vaporize a liquid (for example based on propylene glycol, or glycerin, for example including taste and fragrance ingredients) solution into an aerosol mist. The atomization may be similar to nebulizer or humidifier vaporizing solutions for inhalation. The generated mist may be sensed similarly to cigarette smoke.
A common problem in electronic cigarettes (“e-Cigs”) may be temperature management. The atomization of the liquid requires heating which may be difficult to regulate. Temperature control may be necessary for optimal timing of vaping (i.e. quick response time through the initial heating, for example in the first puff, when the e-Cig is still cool, or after a long break between puffs) without constant over heating that may be draining the battery too quickly unnecessarily. E-Cigs may require a high initial power output to begin the atomization process. The atomization process may be referred to as vaporization although vaporization may just be a secondary effect of the atomization, whereas atomization more accurately simulates smoke. The rapid increase in heat produced may not have enough time to dissipate, resulting in high temperatures internal and external to the housing of the cartridge. The e-liquid and the materials surrounding the heating element may start to overheat and may acquire an unpleasant burning smell (burn out) after reaching a high enough temperature, and the cartomizer housing may become so hot that it may be too warm to hold. Burning may occur when a cartridge filled with a liquid begins to become empty and the heating process occurs without proper control, which may result in bad taste and less pleasure when smoking.
Some e-Cigs use lithium-polymer cells that when fully charged start off with a high voltage of about 4.2 volts, and subsequently drop to about 3.0 volts as the cell's charge is depleted. The smoke/vapor/mist volume may be dependent on the power output. As the cell is depleted, the smoke volume may drop, which creates a less than optimal smoking experience. Accordingly, an e-Cig may not have a uniform and constant smoke volume and smoke temperature due to the variation in frequency and strength of puffs as well as the power output of the cell at any given time.
In particular, e-Cigs may have a circuit to reduce output power by regulating the voltage. The purpose of regulation may be to maximize the amount of puffs available from a fully charged battery as well as deliver a relatively constant voltage to the filament throughout the full smoking cycle. This may ensure that the user has a uniform experience from the first puff to the last, with no degradation in smoke/mist volume and smoke temperature as the battery discharges, while conserving energy and extending battery life. However, in order for a cartomizer to produce enough smoke/mist volume, it may need to be sufficiently warmed up, which may hard to achieve when the voltage is limited to this extent by the regulating circuit. A regulated voltage may therefore not supply enough power to satisfy the requirement for more priming needed to warm up the cartomizer, thus producing less smoke in the beginning, thereby impairing user experience. For a first-time user of the e-Cig, the first few weak puffs with little smoke volume may be a disappointing experience, possibly leading the first time user to discard electronic cigarettes altogether.